Members ksl Posted November 12, 2019 Members Share Posted November 12, 2019 Howdy all~~ My restore of my Gibson GA40 is slowly coming along, and I now want to replace the once present Tremolo Kill Footswitch. I just need to know where the 2 leads go. The top pic shows the inside chassis view of the amp's 6V6 which is the Trem. tube (rectifier directly to the left). Middle shot shows a general area shot between the trem. switch & the trem tube, and the bottom pic shows the bottom of the amp's trem control pot, which has only the 3 trem. speeds. It may be a longshot, but I'd like to pick up a single button footswitch, and as long as there's no lethal charges involved, show me the way!! Thanks all~~ Link to comment Share on other sites More sharing options...
Moderators daddymack Posted November 12, 2019 Moderators Share Posted November 12, 2019 anytime you have capacitors in a circuit you have potential to be shocked fatally. Look up how to safely discharge your caps online, there are plenty of how to's and videos. Do you have the schematic for your amp? If not, I suggest you DL it before you go disconnecting things or poking around...I work on amps periodically and there are so many ways that the unfamiliar DIYer* can mess up and either damage the amp, or hurt themself. did you find the replacement for that gold 150mfd can? As I mentioned in the other thread, there are a number of components that I would likely replace in that amp, mainly capacitors *I'm a familiar DIYer...with decades of electronics experience... Link to comment Share on other sites More sharing options...
Members ksl Posted November 13, 2019 Author Members Share Posted November 13, 2019 Hi daddymack, I fully understand everything you says about the charged caps! No, I have not found those replacement cans...any leads? I would consider myself an intermediate level DIY'er, much better with the non-lethal circuits found in guitars, but I can read & understand a schematic & follow a signal path.....right to those lethal charges, which I know how to discharge, but this restore that I'm up against would be much better dealt with by an expert! Thanks for any tips! Kenny Link to comment Share on other sites More sharing options...
Moderators daddymack Posted November 13, 2019 Moderators Share Posted November 13, 2019 Find a local electronics store or supply house, call them up [i do this frequently] and tell them what you need. Many times, when you tell them you only need one, they will send it as a free sample, or put it on will call for you. I miss Radio Shack! Even here in Los Angeles, nearly all the smaller electronics supply stores are gone...not enough tinkerers left, and with the preponderance of wave soldered circuitry in everything today, parts are getting harder to find. I keep old circuit boards around just to scavenge from....but no, I do not have that 150mfd can available.😉 Link to comment Share on other sites More sharing options...
Members ComingApart Posted January 20, 2020 Members Share Posted January 20, 2020 that amp has a weird trem circuit that uses a tube as an oscillator, as opposed to the standard optocoupler style. can't help you with the switch, but you could tryin pulling the 6SQ7 tube and see if that kills the trem without effecting the operation of the amp. sorry i can't be more helpful. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted January 20, 2020 Members Share Posted January 20, 2020 I doubt a 6V6 in that amp are power tubes, Not rectifier or tremolo tubes. The tremolo is handled by the 6SQ7 tube. The foot switch connects between chassis ground and the 500K pot that controls the tremolo. What the switch essentially does is completes the circuit to the tremolo potentiometer. when the switch is off, the pot does nothing. When the switch is on it adds a ground to the end leg on the potentiometer. The schematic can be found here. https://www.tdpri.com/threads/gibson-ga-40.904898/ Reading a schematic is like reading a road map when driving. If you cant read a road map its unlikely you can read a schematic. Both are abstract drawings involving using abstract images to depict actual objects. Like a road map, a schematic shows where the electricity flows. Reading a schematic and being able to trace every step the signal takes is like reading a road map and knowing which roads you need to travel. An education in electronics teaches you what every component does so you know if the signal is properly manipulated by each component. Test tools let you look inside the circuits and see what the invisible thing called electricity is doing. From there Math is used with the measurements taken to determine if the readings are within tolerance and whether components are doing their jobs properly. If you use these tools and think your way through the problem then you are simply guessing which makes you wide open to making the wrong guesses. Link to comment Share on other sites More sharing options...
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